This invention relates to a die for forming and working metal piece parts. More particularly, it relates to a combination die in which a rotary die cooperates with two progressive die sections to permit complete forming of a metal piece part without a carrier strip.
One conventional method of forming metal piece parts from strip material is to feed that strip material through a progressive die. This feeding, however, requires that excess material, known as a carrier strip, be used either adjacent to or between the parts. This carrier strip guides the movement of the piece part from station to station within the die. In addition, pilot holes carried in the strip, permit accurate positioning of the piece part prior to the closing of the die.
This conventional die performs in an acceptable manner in those instances where the design of the piece part permits its complete formation just prior to its cut off from the carrier strip. Its disadvantage may be the requirement of the excess material.
However, when the piece part requires forming operations both in the direction of feed and in the direction perpendicular to the feed, difficulties arise. That piece part, to permit forming in both directions, must be sheared away from its carrier strip. As a result, it is believed to be standard practice to utilize either excess carrier strip material or two separate dies and presses to form such metal pieces. Under the latter method, a first progressive die is used to partially form the piece parts in one direction. Then, these partially formed parts are severed from the carrier strip, conveyed to a feeder bowl and fed into a second progressive die in the second direction.
To avoid multiple handling problems presented by the use of separate progressive dies, the instant invention utilizes, in one die unit, a progressive die and a rotary die. Examples of a rotary die known to the prior art are depicted in the following U.S. Pat. Nos. 3,827,116; 3,492,681; 3,285,134; 3,150,439; 3,081,655; 2,649,056; 2,415,037; 2,370,828 and 641,725.